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United States Patent | 5,579,654 |
Longsworth ,   et al. | December 3, 1996 |
A closed cycle cryogenic refrigerating system with a fixed restrictor operates with a compressor inlet pressure in a range of 0.1 Mpa to 0.4 Mpa and compressor discharge pressure in a range of 1.5 Mpa and 2.5 Mpa. A basic cryogenic refrigerant mixture is used to which is added approximately 3% to 25% of helium, hydrogen and/or neon. A ratio of refrigerant density at the inlet of the fixed restrictor between steady-state operation and operation at the beginning of cool-down is in an approximate range of 7 to 17. Relatively rapid cool-down is achieved and evaporator temperature is maintained in an approximate range of 70K to 120K.
Inventors: | Longsworth; Ralph C. (Allentown, PA); Boiarsky; Mikhail J. (Moscow, RU); Khatri; Ajay (Bethlehem, PA) |
Assignee: | Apd Cryogenics, Inc. (Allentown, PA) |
Appl. No.: | 496468 |
Filed: | June 29, 1995 |
Current U.S. Class: | 62/511; 62/470; 62/513; 165/58; 165/201 |
Intern'l Class: | F25B 041/06 |
Field of Search: | 62/6,84,498,511,513,468,470 165/58,14 |
3836779 | Sep., 1974 | Bruno | 62/51. |
4094169 | Jun., 1978 | Schmerzler | 62/498. |
4793150 | Dec., 1988 | Wattley et al. | 62/511. |
4949546 | Aug., 1990 | Klusmier et al. | 62/6. |